Starter: 11/27/12 (Keep new paper- Title it 11/27-12/7 Starters)

Starter: 11/27/12(Keep new paper- Title it 11/27-

12/7 Starters) What organs are a part of the cardiovascular

system? What are the functions of this system?

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Cardiovascular System Notes #1: The Heart

Anatomy

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Overview The right side receives

oxygen-poor blood from the body and tissues and then pumps it to the lungs to pick up oxygen and dispel carbon dioxide

Its left side receives oxygenated blood returning from the lungs and pumps this blood throughout the body to supply oxygen and nutrients to the body tissues

The heart=a muscular double pump with 2 functions

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simplified… Cone shaped muscle Four chambers

Two atria, two ventricles Double pump – the ventricles Two circulations

Systemic circuit: blood vessels that transport blood to and from all the body tissues

Pulmonary circuit: blood vessels that carry blood to and from the lungs

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Heart’s position in thorax

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Heart’s position in thorax In mediastinum– behind sternum and pointing

left, lying on the diaphragm It weighs 250-350 gm (about 1 pound)

Feel your heart beat at apex

(this is of a person lying down)

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CXR(chest x ray)

Normal male

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Chest x rays

Normal female Lateral (male)

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Chambers of the heartsides are labeled in reference to the patient facing you

Two atria Right atrium Left atrium

Two ventricles Right ventricle Left ventricle

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Chambers of the heartdivided by septae:

Two atria-divided by interatrial septum Right atrium Left atrium

Two ventricles-divided by interventricular septum Right ventricle Left ventricle

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Valvesthree tricuspidone bicuspid

“Tricuspid” valve RA to RV

Pulmonary or pulmonic valve RV to pulmonary trunk (branches R and L)

Mitral valve (the bicuspid one) LA to LV

Aortic valve LV to aorta

(cusp means flap)

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Function of AV valves

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Function of semilunar valves(Aortic and pulmonic valves)

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Pattern of flow(simple to more detailed)

Body RA RV Lungs LA LV Boby

Body to right heart to lungs to left heart to body

Body, then via vena cavas and coronary sinus to RA, to RV, then to lungs via pulmonary arteries, then to LA via pulmonary veins, to LV, then to body via aorta

From body via SVC, IVC & coronary sinus to RA; then to RV through tricuspid valve; to lungs through pulmonic valve and via pulmonary arteries; to LA via pulmonary veins; to LV through mitral valve; to body via aortic valve then aorta

LEARN THIS

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In the fetus, the RA received oxygenated blood from mom through umbilical cord, so blood R to L through the foramen ovale: fossa ovalis is left after it closes

The pulmonary trunk had high resistance (because lungs not functioning yet) & ductus arteriosus shunted blood to aorta; becomes ligamentum arteriosum after birth

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Note positions of valves Valves open and close in response to pressure differences

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Relative thickness of muscular wallsLV thicker than RV because it forces blood out against more resistance; the systemic circulation is much longer than the pulmonary circulation

Atria are thin because ventricular filling is done by gravity, requiring little atrial effort

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more on valves

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Simplified flow: print and fill in details

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Heartbeat

Systole: contraction Diastole: filling Normal rate: 60-100 Slow: bradycardia Fast: tachycardia

***Note: blood goes to RA, then RV, then lungs, then LA, then LV, then body; but the fact that a given drop of blood passes through the heart chambers sequentially does not mean that the four chambers contract in that order; the 2 atria always contract together, followed by the simultaneous contraction of the 2 ventricles

Definition: a single sequence of atrial contraction followed by ventricular contraction See http://www.geocities.com/Athens/Forum/6100/1heart.html

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Heart sounds

Called S1 and S2 S1 is the closing of AV (Mitral and Tricuspid) valves

at the start of ventricular systole S2 is the closing of the semilunar (Aortic and

Pulmonic) valves at the end of ventricular systole Separation easy to hear on inspiration therefore S2

referred to as A2 and P2 Murmurs: the sound of flow

Can be normal Can be abnormal

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Arch of the

Descending Aorta

Pulmonary Artery

Interventricular Septum

Superior Vena Cava

Inferior Vena Cava

Tricuspid Valve

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another flow chart

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Embryological development during week 4 (helps to understand heart defects)

Day 22, (b) in diagram, heart starts pumping

(day 24)

(day 28)

(day 23)

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Normal andabnormal

Congenital (means born with) abnormalities account for nearly half of all deaths from birth defectsOne of every 150 newborns has some congenital heart defect

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more…

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Use to study